I want to convert the timestamps in a .zsh_history file to their readable equivalents.
Does query-replace-regex or some other function provide the ability to replace the match with the value of a function like something like (format-time-string (match 1))?
: 1568128379:0;cp -a ~/.zshrc.pre-oh-my-zsh ~/.zshrc
: 1568128381:0;exit
UPDATE:
See my solution to this particular problem - https://emacs.stackexchange.com/a/79254/15477
The answer is Yes. C-h f query-replace-regexp says:
In interactive calls, the replacement text can contain ‘\,’ followed by a Lisp expression. Each replacement evaluates that expression to compute the replacement string. Inside of that expression, ‘\&’ is a string denoting the whole match as a string, ‘\N’ for a partial match, ‘\#&’ and ‘\#N’ for the whole or a partial match converted to a number with ‘string-to-number’, and ‘\#’ itself for the number of replacements done so far (starting with zero).
Here is the solution for my .zsh_history example:
The search string: \(: \)\([0-9]\{10\}\)\(:0;\)
The replacement string: \,(concat (format "%6d " (line-number-at-pos)) (rgx-get-time-string (match-string 2)) " "))
A helper function for the unix time string. More of the functionality in the replacement string can be included if preferred.
(defun rgx-get-time-string (unixtimestr)
(format-time-string "%Y-%m-%d %H:%M" (string-to-number unixtimestr))
)
(match-string 2) is an alternate expression for the back reference for the second string \2.
